Protective film for protecting display panel, and display module and display device having the same

ABSTRACT

A display module includes a display panel for displaying an image, and a protective film adhered to a back surface of the display panel. The protective film includes a compensation layer being in contact with the back surface of the display panel, a first release layer disposed under the compensation layer, a cushion layer disposed under the first release layer, and a second release layer disposed under the cushion layer. An adhesive strength of the first release layer is less than an adhesive strength of the second release layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2017-0115417, filed on Sep. 8, 2017, and all the benefits accruingtherefrom under 35 U.S.C. § 119, the content of which in its entirety isherein incorporated by reference.

BACKGROUND 1. Field

Embodiments of the invention relate to a protective film, a displaymodule, a display device, a method of manufacturing a display module,and a method of manufacturing a display device.

2. Description of the Related Art

Display devices are becoming thinner. Thus, if only a compensation layeris adhered to a display panel in a display module, various types ofdefects may occur by a thin thickness of the compensation layer beforeassembling a set. For example, an appearance of the display module maybe damaged by a stab during movement. In particular, when the displaypanel has a flexible film as a base film, malfunction of the displaypanel may occur due to the appearance damage.

SUMMARY

Embodiments of the invention may provide a protective film, a displaymodule, a display device, a method of manufacturing a display module,and a method of manufacturing a display device.

In an aspect of the invention, a display module may include a displaypanel for displaying an image, and a protective film adhered to a backsurface of the display panel. The protective film may include acompensation layer being in contact with the back surface of the displaypanel, a first release layer disposed under the compensation layer, acushion layer disposed under the first release layer, and a secondrelease layer disposed under the cushion layer. An adhesive strength ofthe first release layer may be less than an adhesive strength of thesecond release layer.

A thickness of the cushion layer may be greater than a thickness of thecompensation layer.

The cushion layer may include polymer resin foam.

The first release layer may include a grip portion protruding from anedge of the first release layer in a plan view.

The first release layer may include a first sub-release layer having afirst adhesive strength, and a second sub-release layer having a secondadhesive strength less than the first adhesive strength. The firstadhesive strength and the second adhesive strength may be less than theadhesive strength of the second release layer.

A groove or a hole may be provided in an area of the cushion layer,which overlaps with a boundary between the first sub-release layer andthe second sub-release layer when viewed in a plan view.

The compensation layer may include a first antistatic layer, a coloredlayer disposed under the first antistatic layer; and a second antistaticlayer disposed under the colored layer.

The protective film may further include an adhesive layer disposedbetween the first release layer and the cushion layer to adhere thefirst release layer to the cushion layer.

In an aspect of the invention, a protective film may include aprotective paper, a compensation layer disposed under the protectivepaper, a first release layer disposed under the compensation layer, acushion layer disposed under the first release layer, and a secondrelease layer disposed under the cushion layer. An adhesive strength ofthe first release layer may be less than an adhesive strength of thesecond release layer.

A thickness of the cushion layer may be greater than a thickness of thecompensation layer, and the cushion layer may include polymer resinfoam.

The first release layer may include a grip portion protruding from anedge of the first release layer in a plan view.

The first release layer may include a first sub-release layer having afirst adhesive strength, and a second sub-release layer having a secondadhesive strength less than the first adhesive strength.

A groove or a hole may be provided in an area of the cushion layer,which overlaps with a boundary between the first sub-release layer andthe second sub-release layer when viewed in a plan view.

The protective film may further include an adhesive layer disposedbetween the first release layer and the cushion layer to adhere thefirst release layer to the cushion layer.

The compensation layer may include a glue layer disposed under theprotective paper, a first antistatic layer disposed under the gluelayer, a colored layer disposed under the first antistatic layer, and asecond antistatic layer disposed under the colored layer.

In an aspect of the invention, a method of manufacturing a displaymodule may include aligning a protective film, which includes acompensation layer, a first release layer disposed under thecompensation layer and having a first adhesive strength, a cushion layerdisposed under the first release layer, and a second release layerdisposed under the cushion layer and having a second adhesive strengthgreater than the first adhesive strength, with a back surface of adisplay panel, and adhering the protective film to the display panel insuch a way that the compensation layer is in contact with the backsurface of the display panel.

The method may further include separating the first release layer fromthe compensation layer adhered to the display panel.

The first release layer may include a first sub-release layer having athird adhesive strength greater than the first adhesive strength andless than the second adhesive strength, and a second sub-release layerhaving the first adhesive strength. In this case, the method may furtherinclude separating the second sub-release layer from the compensationlayer adhered to the display panel.

The method may further include providing a groove or a hole in an areaof the cushion layer, which overlaps with a boundary between the firstsub-release layer and the second sub-release layer.

In an aspect of the invention, a method of manufacturing a displaydevice may include aligning a protective film, which includes acompensation layer, a first release layer disposed under thecompensation layer, a cushion layer disposed under the first releaselayer, and a second release layer disposed under the cushion layer, witha back surface of a display panel, adhering the protective film to thedisplay panel in such a way that the compensation layer is in contactwith the back surface of the display panel, and separating the firstrelease layer from the compensation layer being in contact with thedisplay panel.

An adhesive strength of the first release layer may be less than anadhesive strength of the second release layer.

The first release layer may include a first sub-release layer having afirst adhesive strength, and a second sub-release layer having a secondadhesive strength less than the first adhesive strength. In this case,only the second sub-release layer of the first and second sub-releaselayers may be separated in the separating of the first release layer.

The method may further include providing a groove or a hole in an areaof the cushion layer, which overlaps with a boundary between the firstsub-release layer and the second sub-release layer.

In an aspect of the invention, a display device may include a displaypanel for displaying an image, a protective film adhered to a backsurface of the display panel, and a bracket disposed under theprotective film. The protective film may include a compensation layerbeing in contact with the back surface of the display panel andincluding a first area and a second area, a first release layer disposedunder the compensation layer, and a cushion layer disposed under thefirst release layer. The first release layer and the cushion layer mayoverlap with the first area and may not overlap with the second area,when viewed in a plan view.

A concave region may be provided in an area of the bracket, whichoverlaps with the first area in a plan view.

A central portion of the protective film may be defined as the firstarea and an outer portion of the protective film may be defined as thesecond area, when viewed in a plan view.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present invention willbecome more apparent by describing in further detail exemplaryembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective view illustrating a display device according toan embodiment of the invention;

FIG. 2 is an exploded perspective view illustrating a display deviceaccording to an embodiment of the invention;

FIG. 3A is a cross-sectional view illustrating some components of adisplay device according to an embodiment of the invention;

FIG. 3B is a cross-sectional view illustrating some components of adisplay device according to an embodiment of the invention;

FIGS. 4 and 5 are cross-sectional views illustrating a method ofmanufacturing a display module according to an embodiment of theinvention;

FIG. 6 is a cross-sectional view illustrating a compensation layeraccording to an embodiment of the invention;

FIG. 7 is a cross-sectional view illustrating an operation of separatingsome of components of a protective film from a display module beforeassembling a set;

FIG. 8 is a perspective view illustrating a protective film according toan embodiment of the invention;

FIG. 9 is a cross-sectional view illustrating an operation of assemblinga set according to an embodiment of the invention;

FIG. 10 is a cross-sectional view illustrating a protective filmaccording to an embodiment of the invention;

FIG. 11 is a cross-sectional view illustrating a display moduleaccording to an embodiment of the invention;

FIG. 12 is a cross-sectional view illustrating an operation ofseparating some components of a protective film from a display modulebefore assembling a set;

FIG. 13 is a cross-sectional view illustrating an operation ofassembling a set according to an embodiment of the invention;

FIG. 14 is a plan view illustrating a protective film according to anembodiment of the invention;

FIG. 15A is a cross-sectional view taken along a line I-I′ of FIG. 14;

FIG. 15B is a cross-sectional view taken along the line I-I′ of FIG. 14to illustrate a protective film according to another embodiment of theinvention;

FIG. 16 is a plan view illustrating a protective film according to anembodiment of the invention;

FIG. 17 is a cross-sectional view taken along a line II-II′ of FIG. 16;and

FIG. 18 is a plan view illustrating a protective film according to anembodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention will now be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element such as a layer, region orsubstrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may be present. Incontrast, the term “directly” means that there are no interveningelements. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items. Theterminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings herein.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system).

Exemplary embodiments are described herein with reference tocross-sectional illustrations and/or plane illustrations that areidealized exemplary illustrations. In the drawings, the thicknesses oflayers and regions are exaggerated for clarity. Accordingly, variationsfrom the shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, are to be expected. Thus,exemplary embodiments should not be construed as limited to the shapesof regions illustrated herein but are to include deviations in shapesthat result, for example, from manufacturing. For example, an etchingregion illustrated as a rectangle will, typically, have rounded orcurved features. Thus, the regions illustrated in the figures areschematic in nature and their shapes are not intended to illustrate theactual shape of a region of a device and are not intended to limit thescope of exemplary embodiments.

FIG. 1 is a perspective view illustrating a display device according toan embodiment of the invention.

Referring to FIG. 1, a display device DD may display an image IM througha display surface IS. In FIG. 1, the display surface IS may be parallelto a plane defined by a first direction DR1 and a second direction DR2intersecting the first direction DR1. However, embodiments of theinvention are not limited thereto. In another embodiment, a displaysurface (not shown) of a display device (not shown) may have a bent orcurved shape.

A normal direction of the display surface IS (i.e., a thicknessdirection of the display device DD) is indicated by a third directionDR3. A front surface (or a top surface) and a back surface (or a bottomsurface) of each of members are defined by the third direction DR3.However, directions indicated by the first to third directions DR1, DR2and DR3 may be relative concepts and may be changed into otherdirections. Hereinafter, first to third directions are the directionsindicated by the first to third directions DR1, DR2 and DR3,respectively, and are indicated by the same reference designators.

In FIG. 1, a portable electronic device is illustrated as an example ofthe display device DD. However, in other embodiments, the display deviceDD may also be applied to large-sized electronic devices (e.g.,televisions, monitors, and external billboards) and small andmiddle-sized electronic devices (e.g., personal computers, notebookcomputers, personal digital assistants (PDAs), car navigation units,game consoles, smart phones, tablets, and cameras). However, these areprovided only as embodiments of the invention. In still otherembodiments, the display device DD may be applied to other variouselectronic devices as long as they do not depart from the spirits andscopes of the invention.

The display surface IS includes a display area DD-DA in which the imageIM is displayed, and a non-display area DD-NDA adjacent to the displayarea DD-DA. An image is not displayed in the non-display area DD-NDA. InFIG. 1, application icons are illustrated as an example of the image IM.For example, the display area DD-DA may have a quadrilateral shape(e.g., a rectangular shape). The non-display area DD-NDA may surroundthe display area DD-DA. However, embodiments of the invention are notlimited thereto. The shapes of the display area DD-DA and thenon-display area DD-NDA may have other designs. In certain embodiments,the non-display area DD-NDA may not exist in a front surface of thedisplay device DD.

FIG. 2 is an exploded perspective view illustrating the display deviceDD according to an embodiment of the invention, and FIG. 3A is across-sectional view illustrating some components of the display deviceDD according to an embodiment of the invention.

Referring to FIGS. 2 and 3A, the display device DD may include a window100, a display panel 200, a sensing unit 300, a compensation layer 400,a bracket 500, an electronic component 600, and a back case 700. In FIG.3A, the bracket 500, the electronic component 600 and the back case 700of FIG. 2 are omitted for the purpose of ease and convenience indescription and illustration.

The window 100 may be disposed over the display panel 200. The window100 may include glass, sapphire, or plastic. However, these materialsare provided only as examples of the material of the window 100, and inother embodiments, the window 100 may include a transparent materialthat is capable of transmitting an image (see IM of FIG. 1) provided bythe display panel 200.

The display panel 200 may provide an image (see IM of FIG. 1).Hereinafter, an organic light emitting display panel will be describedas an example of the display panel 200. However, embodiments of theinvention are not limited thereto. In other embodiments, the displaypanel 200 may be a liquid crystal display panel, a plasma display panel,or an electrophoretic display panel.

The display panel 200 may include a base film BS, a circuit layer ML, alight emitting element layer EL, and a thin film encapsulation layerECL.

The base film BS may be a flexible film or a rigid film. For example,the base film BS may include a plastic film, a glass film, a metal film,or an organic/inorganic composite film. The plastic film may include atleast one of an acrylic-based resin, a methacrylic-based resin,polyisoprene, a vinyl-based resin, an epoxy-based resin, aurethane-based resin, a cellulose-based resin, a siloxane-based resin, apolyimide-based resin, a polyamide-based resin, or a perylene-basedresin.

The circuit layer ML may include a plurality of insulating layers, aplurality of conductive layers, and a semiconductor layer. The pluralityof conductive layers of the circuit layer ML may include signal linesand/or a control circuit of a pixel.

The light emitting element layer EL may include a display element, e.g.,an organic light emitting diode. However, embodiments of the inventionare not limited thereto. In other embodiments, the light emittingelement layer EL may include an inorganic light emitting diode or anorganic-inorganic hybrid light emitting diode, depending on the type ofthe display panel 200.

The thin film encapsulation layer ECL encapsulates the light emittingelement layer EL. The thin film encapsulation layer ECL may include aplurality of inorganic thin films and at least one organic thin filmdisposed therebetween. The inorganic thin films protect the lightemitting element layer EL from water and oxygen, and the organic thinfilm protects the light emitting element layer EL from a foreignmaterial such as dust particles.

The sensing unit 300 may be disposed on the display panel 200. Thesensing unit 300 may sense an external input by a resistive film method,a mutual capacitance method, a self-capacitance method, or anelectromagnetic induction method. However, the operating method of thesensing unit 300 is not limited to these embodiments.

The external input provided from the outside may be various and may be,for example, a part of a body of a user, a stylus pen, light, heat, orpressure. In addition, the sensing unit 300 may sense a touch of a part(e.g., a finger) of a body of a user and may also sense an approachingspatial touch (e.g., a hovering touch). The sensing unit 300 accordingto the embodiment of the invention may sense at least one of variouskinds of touches and is not limited to a specific embodiment.

A first adhesive member AHL1 may be disposed between the display panel200 and the sensing unit 300, and a second adhesive member AHL2 may bedisposed between the sensing unit 300 and the window 100. Each of thefirst and second adhesive members AHL1 and AHL2 may be an organicadhesive layer such as an optically clear adhesive (OCA) film, anoptically clear resin (OCR), or a pressure sensitive adhesive (PSA)film. The organic adhesive layer may include an adhesive material suchas a polyurethane-based adhesive material, a polyacryl-based adhesivematerial, a polyester-based adhesive material, a polyepoxy-basedadhesive material, or a polyacetate vinyl-based adhesive material.

The compensation layer 400 may be disposed under the display panel 200.The compensation layer 400 may be adhered to a back surface BL of thedisplay panel 200. The compensation layer 400 may block staticelectricity provided from the outside or static electricity provided inan electrostatic discharge (ESD) test. The compensation layer 400 mayinclude a colored layer to prevent light incident on the compensationlayer 400 from being reflected again to the outside, and thus componentsdisposed under the display panel 200 may not be visible.

The display device DD may further include a flexible printed circuitboard FPCB and a printed circuit board PCB.

The flexible printed circuit board FPCB electrically connects thedisplay panel 200 to the printed circuit board PCB. One end of theflexible printed circuit board FPCB may be connected to a surface of thebase film BS exposed by the thin film encapsulation layer ECL, andanother end of the flexible printed circuit board FPCB may be connectedto the printed circuit board PCB. The flexible printed circuit boardFPCB may be flexibly provided to be bent toward the back surface BL ofthe display panel 200 in a state in which the flexible printed circuitboard FPCB is connected or coupled to the display panel 200 and theprinted circuit board PCB.

The printed circuit board PCB may transmit signals to the display panel200 through the flexible printed circuit board FPCB and/or may receivesignals from the display panel 200 through the flexible printed circuitboard FPCB. Since the flexible printed circuit board FPCB is bent, theprinted circuit board PCB may be disposed under the display panel 200 ina state in which the printed circuit board PCB is connected or coupledto the flexible printed circuit board FPCB. A connector (not shown) forreceiving signals from an external system may be connected to theprinted circuit board PCB.

The bracket 500 may be disposed under the display panel 200 to supportthe display panel 200. The back case 700 may be coupled to the window100 to receive the display panel 200. The back case 700 may includeplastic or metal. A space may be defined between the bracket 500 and theback case 700, and the electronic component 600 may be disposed in thespace. The electronic component 600 may be, for example, a batteryand/or a camera module.

FIG. 3B is a cross-sectional view illustrating some components of adisplay device according to an embodiment of the invention. In theembodiment of FIG. 3B, the same components as in the embodiment of FIG.3A will be indicated by the same reference numerals or designators, andthe descriptions thereto will be omitted.

Referring to FIG. 3B, the display panel 200 and the sensing unit 300 maybe manufactured by continuous processes. Thus, the first adhesive memberAHL1 illustrated in FIG. 3A may be omitted in the present embodiment. Inthis case, the thin film encapsulation layer ECL may further include abuffer layer. The buffer layer may be a layer closest to the sensingunit 300. The buffer layer may be an inorganic layer or an organiclayer. The inorganic layer may include at least one of silicon nitride,silicon oxynitride, silicon oxide, titanium oxide, or aluminum oxide.The organic layer may include a polymer, e.g., an acrylic-based organiclayer. However, embodiments of the invention are not limited thereto.

FIGS. 4 and 5 are cross-sectional views illustrating a method ofmanufacturing a display module according to an embodiment of theinvention.

Referring to FIG. 4, a display panel 200 is provided. The display panel200 is the same as described above with reference to FIG. 3A.

In FIG. 4, only the display panel 200 is illustrated. However, thedisplay panel 200 may be provided in a state in which the flexibleprinted circuit board FPCB (see FIG. 3A) and the printed circuit boardPCB (see FIG. 3A) are adhered to the display panel 200. Alternatively,the display panel 200 may be provided before the flexible printedcircuit board FPCB and the printed circuit board PCB are adhered to thedisplay panel 200. In other embodiments, the sensing unit 300 (see FIG.3A) and the display panel 200 adhered to each other may be provided, orthe display panel 200 may be provided before the sensing unit 300 (seeFIG. 3A) is adhered to the display panel 200. In still otherembodiments, the display panel 200 may be provided after the sensingunit 300 (see FIG. 3B) is formed on the display panel 200.

Referring to FIG. 5, a protective film PF may be aligned with the backsurface BL of the display panel 200. The protective film PF may includea compensation layer 400, a first release layer 410, an adhesive layer420, a cushion layer 430, and a second release layer 440.

The first release layer 410 may be disposed under the compensation layer400, and the adhesive layer 420 may be disposed under the first releaselayer 410. The cushion layer 430 may be disposed under the adhesivelayer 420, and the second release layer 440 may be disposed under thecushion layer 430.

The protective film PF may be adhered to the display panel 200 in such away that the compensation layer 400 is in contact with the back surfaceBL of the display panel 200. The back surface BL of the display panel200 may be a surface opposite to a surface on which an image isdisplayed. The protective film PF may be adhered to the back surface BLof the display panel 200 to form a display module DM.

Even though not shown in FIG. 5, a protective paper may further beprovided on the compensation layer 400. In this case, to adhere thecompensation layer 400 to the back surface BL of the display panel 200,the method of manufacturing the display module may further include anoperation of removing the protective paper.

The compensation layer 400 may be an optical compensation layer thatblocks static electricity and/or prevents components disposed under thedisplay panel 200 from being visible to a user.

The compensation layer 400 may be adhered to one surface of the firstrelease layer 410, and the cushion layer 430 may be disposed on anothersurface of the first release layer 410 with the adhesive layer 420interposed therebetween. In the event that the cushion layer 430includes with it an adhesive layer, the separately provided adhesivelayer 420 may be omitted. An adhesive strength of the first releaselayer 410 may be 4 gf/25 mm or less.

The adhesive layer 420 may include an adhesive material such as apolyurethane-based adhesive material, a polyacryl-based adhesivematerial, a polyester-based adhesive material, a polyepoxy-basedadhesive material, or a polyacetate vinyl-based adhesive material.However, the material of the adhesive layer 420 is not limited thereto.

The cushion layer 430 may include polymer resin foam. For example, thecushion layer 430 may include foam formed of polyurethane,polycarbonate, polypropylene, polyethylene, or polyolefin. However, thematerial of the cushion layer 430 is not limited thereto.

The second release layer 440 is adhered to the cushion layer 430. Anadhesive strength of the second release layer 440 may be greater thanthe adhesive strength of the first release layer 410. For example, theadhesive strength of the second release layer 440 may be 150 or moretimes greater than the adhesive strength of the first release layer 410.However, the 150 times is merely an example for explaining a largedifference in adhesive strength. The second release layer 440 may havean adhesive strength of 700 gf/25 mm or more. For example, the secondrelease layer 440 may have an adhesive strength of 731 gf/25 mm.

Thereafter, the display module DM may be assembled with various sets ofcomponents to realize various types of the display devices DD (see FIG.1). The state in which the protective film PF is adhered to the displaypanel 200 may be maintained before the display module DM is assembledwith the set.

In an embodiment of the invention, a first thickness TN1 of thecompensation layer 400 may be less than a second thickness TN2 of thecushion layer 430. For example, the first thickness TN1 of thecompensation layer 400 may be 0.03 mm, and the second thickness TN2 ofthe cushion layer 430 may be 0.1 mm or more.

The display device DD (see FIG. 1) may become thinner. Therefore, ifonly the compensation layer 400 is adhered to the display panel 200,various types of defects may occur before assembling the set since thecompensation layer 400 is thin. For example, an appearance of thedisplay module DM may be damaged by a stab during movement. Inparticular, when the base film BS (see FIG. 3A) is a flexible film,malfunction of the display panel 200 may occur due to the appearancedamage. However, according to the embodiments of the invention, thecushion layer 430 having a thickness of 0.1 mm or more is provided underthe compensation layer 400. Thus, the display panel 200 may be protectedby the cushion layer 430 before the display module DM is assembled withthe set.

The first release layer 410 may be separated from the compensation layer400 adhered to the display panel 200 before the set assembly, and thusthe first release layer 410, the adhesive layer 420, the cushion layer430 and the second release layer 440 may be separated from the displaypanel 200. Thus, when the thinned display device DD (see FIG. 1) ismanufactured, it is possible to inhibit or prevent defects fromoccurring at the display module DM before assembling the set.

FIG. 6 is a cross-sectional view illustrating a compensation layeraccording to an embodiment of the invention. However, components of thecompensation layer 400 are not limited to FIG. 6 but may be variouslymodified or changed.

Referring to FIGS. 5 and 6, the compensation layer 400 may include aglue layer 401, a first antistatic layer 402, a colored layer 403, and asecond antistatic layer 404.

The glue layer 401 may be adhered to the back surface BL of the displaypanel 200. The glue layer 401 may include a silicone adhesive.

The first antistatic layer 402 and the second antistatic layer 404 mayblock the static electricity provided from the outside and/or the staticelectricity provided in the ESD test. In other embodiments of theinvention, one of the first antistatic layer 402 and the secondantistatic layer 404 may be omitted, or both the first antistatic layer402 and the second antistatic layer 404 may be omitted.

The colored layer 403 may prevent light incident on the compensationlayer 400 from being reflected again to the outside, and thus componentsdisposed under the display panel 200 may not be visible. The coloredlayer 403 may include blue ink or black ink. However, the color of thecolored layer 403 is not limited thereto. The colored layer 403 may beprovided by printing the blue ink or the black ink onto the firstantistatic layer 402 or the second antistatic layer 404.

FIG. 7 is a cross-sectional view illustrating an operation of separatingsome components of the protective film PF from the display module DMbefore assembling the set.

Referring to FIG. 7, the first release layer 410 of the protective filmPF may be separated from the display panel 200 and the compensationlayer 400, as described above. In other words, the cushion layer 430protecting the back surface of the display panel 200 may be separatedfrom the compensation layer 400 before assembling the set.

Even though only the compensation layer 400 is disposed on the backsurface of the display panel 200 by the demand for thinning the displaydevice DD (see FIG. 1), the display panel 200 is protected by thecushion layer 430 before the display panel 200 is assembled in the set.Thus, an occurrence rate of defects of the display module DM may bereduced or minimized.

FIG. 8 is a perspective view illustrating a protective film PF accordingto an embodiment of the invention.

A protective paper 400 p disposed on the compensation layer 400 isfurther illustrated in the protective film PF of FIG. 8. The protectivepaper 400 p may be removed before the protective film PF is adhered tothe display panel 200 (see FIG. 7). A grip portion 400 p-H may furtherbe provided to the protective paper 400 p to easily separate theprotective paper 400 p from the compensation layer 400.

A grip portion 410-H may be provided to easily separate the firstrelease layer 410, the adhesive layer 420, the cushion layer 430 and thesecond release layer 440 from the compensation layer 400 beforeassembling the set.

The grip portion 410-H may be connected to the first release layer 410.For example, the grip portion 410-H may protrude from one edge EG of thefirst release layer 410 when viewed in a plan view. In an embodiment ofthe invention, the grip portion 410-H may be a component included in thefirst release layer 410.

In FIG. 8, one surface of the grip portion 410-H has a rectangularshape. However, embodiments of the invention are not limited thereto. Aposition, a shape and a size of the grip portion 410-H may be modifiedin other embodiments.

The grip portion 400 p-H of the protective paper 400 p and the gripportion 410-H of the first release layer 410 may be disposed atdifferent positions from each other when viewed in a plan view.

FIG. 9 is a cross-sectional view illustrating an operation of assemblinga set according to an embodiment of the invention.

As illustrated in FIG. 7, the first release layer 410, the adhesivelayer 420, the cushion layer 430 and the second release layer 440 areseparated from the display panel 200 except the compensation layer 400.Thereafter, the bracket 500, the electronic component 600 and the backcase 700 may be coupled to the back surface of the display panel 200 towhich the compensation layer 400 is adhered, thereby constituting orassembling the set. However, embodiments of the invention are notlimited thereto. The method of assembling the set may be modified inother embodiments. For example, the bracket 500 may be omitted incertain embodiments.

FIG. 10 is a cross-sectional view illustrating a protective film PFaaccording to an embodiment of the invention. In the embodiment of FIG.10, the same components as in the embodiment of FIG. 5 will be indicatedby the same reference numerals or designators, and the descriptionsthereto will be omitted.

The protective film PFa may include the compensation layer 400, a firstrelease layer 410 a, an adhesive layer 420-1 and 420-2, a cushion layer430-1 and 430-2, and the second release layer 440.

The first release layer 410 a may include a first sub-release layer410-1 having a first adhesive strength and a second sub-release layer410-2 having a second adhesive strength less than the first adhesivestrength.

The first adhesive strength of the first sub-release layer 410-1 may begreater than the second adhesive strength of the second sub-releaselayer 410-2 and may be less than the adhesive strength of the secondrelease layer 440. For example, the second adhesive strength of thesecond sub-release layer 410-2 may be 4 gf/25 mm or less, and theadhesive strength of the second release layer 440 may be 700 gf/25 mm ormore. Thus, the first adhesive strength of the first sub-release layer410-1 may be greater than 4 gf/25 mm and less than 700 gf/25 mm. Inparticular, the first adhesive strength of the first sub-release layer410-1 may range from 100 gf/25 mm to 300 gf/25 mm.

FIG. 11 is a cross-sectional view illustrating a display module DMaaccording to an embodiment of the invention, FIG. 12 is across-sectional view illustrating an operation of separating somecomponents of a protective film from the display module DMa beforeassembling a set, and FIG. 13 is a cross-sectional view illustrating anoperation of assembling a set according to an embodiment of theinvention.

Referring to FIGS. 11 to 13, a protective film PFa is adhered to theback surface of the display panel 200 to form a display module DMa. Theprotective film PFa is the same as described above with reference toFIG. 10.

The protective film PFa may include a first area RMA and a second areaRA. The first area RMA may be defined as an area overlapping with thefirst sub-release layer 410-1 and the second area RA may be defined asan area overlapping with the second sub-release layer 410-2, when viewedin a plan view. Here, when an component is viewed in the plan view, itmay be viewed in a direction parallel to the third direction DR3.

Portions, overlapping with the first area RMA, of the adhesive layer420-1 and 420-2 and the cushion layer 430-1 and 430-2 are defined as afirst adhesive layer 420-1 and a first cushion layer 430-1,respectively. Portions, overlapping with the second area RA, of theadhesive layer 420-1 and 420-2 and the cushion layer 430-1 and 430-2 aredefined as a second adhesive layer 420-2 and a second cushion layer430-2, respectively.

In FIG. 12, the second sub-release layer 410-2 is separated from thecompensation layer 400 before assembling a set. In other words, thesecond sub-release layer 410-2, the second adhesive layer 420-2, thesecond cushion layer 430-2 and the second release layer 440 may beseparated from the display panel 200. Thus, the compensation layer 400,the first sub-release layer 410-1, the first adhesive layer 420-1 andthe first cushion layer 430-1 may remain on the back surface of thedisplay panel 200.

Referring to FIG. 13, a bracket 500-1, the electronic component 600 andthe back case 700 may be coupled to the back surface of the displaypanel 200 to assemble a set.

The compensation layer 400 is adhered to an entire portion of the backsurface of the display panel 200, and the first sub-release layer 410-1,the first adhesive layer 420-1 and the first cushion layer 430-1 aredisposed under only a partial area of the compensation layer 400. Thefirst sub-release layer 410-1, the first adhesive layer 420-1 and thefirst cushion layer 430-1 may overlap with the first area RMA (see FIG.11) but may not overlap with the second area RA (see FIG. 11), whenviewed in a plan view.

A concave region 500-1H may be provided at the bracket 500-1. A positionof the concave region 500-1H may correspond to a position at which thefirst sub-release layer 410-1, the first adhesive layer 420-1 and thefirst cushion layer 430-1 are disposed. For example, the concave region500-1H may overlap with the first area RMA (see FIG. 11) when viewed ina plan view.

A space in which a cushion layer will be adhered may be provided on apartial area of the back surface of the display panel 200 by the concaveregion 500-1H of the bracket 500-1. Thus, the second sub-release layer410-2, the second adhesive layer 420-2 and the second cushion layer430-2 may be removed from a partial area (e.g., the second area RA) tosatisfy the demand for thinning the display device DD (see FIG. 1), andthe first sub-release layer 410-1, the first adhesive layer 420-1 andthe first cushion layer 430-1 may remain in another partial area (e.g.,the first area RMA).

FIG. 14 is a plan view illustrating a protective film PFa according toan embodiment of the invention.

Referring to FIGS. 11 and 14, a hole HL may be defined at a boundarybetween the first area RMA and the second area RA of the protective filmPFa. The hole HL is illustrated by a solid line at the boundary of thefirst area RMA and the second area RA to clarify the understanding.However, the hole HL is not necessarily formed in all components or anoutermost component of the protective film PFa. This will be describedin detail with reference to FIGS. 15A and 15B.

The grip portion 410-H of the protective film PFa may extend from thesecond sub-release layer 410-2 described above. The second sub-releaselayer 410-2 may be easily separated from the compensation layer 400 byusing the grip portion 410-H.

FIGS. 15A and 15B are cross-sectional views taken along a line I-I′ ofFIG. 14.

Referring to FIG. 15A, the hole HL may be provided at a boundary betweenthe first adhesive layer 420-1 and the second adhesive layer 420-2 and aboundary between the first cushion layer 430-1 and the second cushionlayer 430-2 to easily separate the second adhesive layer 420-2 and thesecond cushion layer 430-2 from the first adhesive layer 420-1 and thefirst cushion layer 430-1. Since the second release layer 440 is removedbefore assembling the set, the hole HL may not be provided in the secondrelease layer 440.

Referring to FIG. 15B, a hole HLa may extend into the second releaselayer 440.

Even though not shown in the drawings, in another embodiment of theinvention, the first adhesive layer 420-1 and the second adhesive layer420-2 may be provided separately, and the first cushion layer 430-1 andthe second cushion layer 430-2 may be provided separately. In otherwords, the first adhesive layer 420-1 may be disposed separately fromthe second adhesive layer 420-2, and the first cushion layer 430-1 maybe disposed separately from the second cushion layer 430-2. In stillanother embodiment of the invention, one of the boundary of the firstand second adhesive layers 420-1 and 420-2 and the boundary of the firstand second cushion layers 430-1 and 430-2 may be cut, and a hole may beprovided at the other of the boundary of the first and second adhesivelayers 420-1 and 420-2 and the boundary of the first and second cushionlayers 430-1 and 430-2.

FIG. 16 is a plan view illustrating a protective film according to anembodiment of the invention, and FIG. 17 is a cross-sectional view takenalong a line II-II′ of FIG. 16.

Referring to FIG. 16, a groove HM may be provided at the boundarybetween the first area RMA and the second area RA of the protective filmPFa. The groove HM is illustrated at the boundary between the first areaRMA and the second area RA for the purpose of ease and convenience indescription and illustration. However, the groove HM is not necessarilyprovided in all components or an outermost component of the protectivefilm PFa.

Referring to FIG. 17, the groove HM may be provided at the boundarybetween the first adhesive layer 420-1 and the second adhesive layer420-2 and the boundary between the first cushion layer 430-1 and thesecond cushion layer 430-2. FIG. 17 illustrates the groove HM whichpenetrates the boundary between the first and second adhesive layers420-1 and 420-3 and extends into a portion of the boundary between thefirst and second cushion layers 430-1 and 430-2. However, embodiments ofthe invention are not limited thereto. A depth HDT of the groove HM maybe variously adjusted. In other words, in FIG. 17, the depth HDT of thegroove HM is greater than a thickness of the first adhesive layer 420-1and is less than a sum of the thickness of the first adhesive layer420-1 and a thickness of the first cushion layer 430-1. However,embodiments of the invention are not limited thereto. In anotherembodiment of the invention, the depth HDT of the groove HM may be equalto the sum of the thickness of the first adhesive layer 420-1 and thethickness of the first cushion layer 430-1. In still another embodimentof the invention, the depth HDT of the groove HM may be greater than thesum of the thickness of the first adhesive layer 420-1 and the thicknessof the first cushion layer 430-1, and thus the groove HM may also beprovided in the second release layer 440. In yet other embodiments, thegroove HM may be provided in only an area corresponding to the boundarybetween the first and second adhesive layers 420-1 and 420-2 or may beprovided in only an area corresponding to the boundary between the firstand second cushion layers 430-1 and 430-2.

FIG. 18 is a plan view illustrating a protective film according to anembodiment of the invention.

FIG. 18 illustrates an embodiment in which positions of a first areaRMAa and a second area RAa of a protective film PFb can be variouslychanged depending on a design.

For example, the thin display device DD (see FIG. 1) may be provided byreducing a thickness of an outermost portion of the display device DD(see FIG. 1). In this case, a space in which the cushion layer will bedisposed may be defined in an area corresponding to a central portion ofthe display device DD (see FIG. 1).

Thus, as illustrated in FIG. 18, the first area RMAa may be defined in acentral portion of the protective film PFb, and the second area RAa maybe defined in an outer portion of the protective film PFb. As describedabove with reference to FIGS. 10 to 12, a first release layer, anadhesive layer and a cushion layer of the protective film PFb, whichoverlap with the first area RMAa in a plan view, may be provided to beadhered to the display panel 200 (see FIG. 4). On the other hand, thefirst release layer, the adhesive layer and the cushion layer of theprotective film PFb, which overlap with the second area RAa in a planview, may be separated from the compensation layer. In addition, eventhough not shown in the drawings, the groove or the hole may be providedat a boundary between the first area RMAa and the second area RAa, asdescribed with reference to FIGS. 14 to 17.

Display devices are becoming thinner. Thus, if only a compensation layeris adhered to a display panel in a display module, various types ofdefects may occur by a thin thickness of the compensation layer beforeassembling a set. For example, an appearance of the display module maybe damaged by a stab during movement. In particular, when the displaypanel has a flexible film as a base film, malfunction of the displaypanel may occur due to the appearance damage. However, according to theembodiments of the invention, the cushion layer is disposed under thecompensation layer and is adhered to the compensation layer. Thus, theback surface of the display panel may be protected by the cushion layerbefore the display module is assembled with the set.

While the invention has been described with reference to exampleembodiments, it will be apparent to those skilled in the art thatvarious changes and modifications may be made without departing from thespirits and scopes of the invention. Therefore, it should be understoodthat the above embodiments are not limiting, but illustrative. Thus, thescopes of the invention are to be determined by the broadest permissibleinterpretation of the following claims and their equivalents, and shallnot be restricted or limited by the foregoing description.

What is claimed is:
 1. A display module comprising: a display panel fordisplaying an image; and a protective film adhered to a back surface ofthe display panel, wherein the protective film comprises: a compensationlayer being in contact with the back surface of the display panel; afirst release layer disposed under the compensation layer; a cushionlayer disposed under the first release layer; and a second release layerdisposed under the cushion layer, wherein an adhesive strength of thefirst release layer is less than an adhesive strength of the secondrelease layer.
 2. The display module of claim 1, wherein a thickness ofthe cushion layer is greater than a thickness of the compensation layer.3. The display module of claim 1, wherein the cushion layer includespolymer resin foam.
 4. The display module of claim 1, wherein the firstrelease layer comprises a grip portion protruding from an edge of thefirst release layer in a plan view.
 5. The display module of claim 1,wherein the first release layer comprises: a first sub-release layerhaving a first adhesive strength; and a second sub-release layer havinga second adhesive strength less than the first adhesive strength, andwherein the first adhesive strength and the second adhesive strength areless than the adhesive strength of the second release layer.
 6. Thedisplay module of claim 5, wherein a groove or a hole is provided in anarea of the cushion layer, which overlaps with a boundary between thefirst sub-release layer and the second sub-release layer when viewed ina plan view.
 7. The display module of claim 1, wherein the compensationlayer comprises: a first antistatic layer; a colored layer disposedunder the first antistatic layer; and a second antistatic layer disposedunder the colored layer.
 8. The display module of claim 1, wherein theprotective film further comprises: an adhesive layer disposed betweenthe first release layer and the cushion layer to adhere the firstrelease layer to the cushion layer.
 9. A protective film comprising: aprotective paper; a compensation layer disposed under the protectivepaper; a first release layer disposed under the compensation layer; acushion layer disposed under the first release layer; and a secondrelease layer disposed under the cushion layer, wherein an adhesivestrength of the first release layer is less than an adhesive strength ofthe second release layer.
 10. The protective film of claim 9, wherein athickness of the cushion layer is greater than a thickness of thecompensation layer, and wherein the cushion layer includes polymer resinfoam.
 11. The protective film of claim 9, wherein the first releaselayer comprises a grip portion protruding from an edge of the firstrelease layer in a plan view.
 12. The protective film of claim 9,wherein the first release layer comprises: a first sub-release layerhaving a first adhesive strength; and a second sub-release layer havinga second adhesive strength less than the first adhesive strength. 13.The protective film of claim 12, wherein a groove or a hole is providedin an area of the cushion layer, which overlaps with a boundary betweenthe first sub-release layer and the second sub-release layer when viewedin a plan view.
 14. The protective film of claim 9, further comprising:an adhesive layer disposed between the first release layer and thecushion layer to adhere the first release layer to the cushion layer.15. The protective film of claim 9, wherein the compensation layercomprises: a glue layer disposed under the protective paper; a firstantistatic layer disposed under the glue layer; a colored layer disposedunder the first antistatic layer; and a second antistatic layer disposedunder the colored layer.
 16. A display device comprising: a displaypanel for displaying an image; a protective film adhered to a backsurface of the display panel; and a bracket disposed under theprotective film, wherein the protective film comprises: a compensationlayer being in contact with the back surface of the display panel andincluding a first area and a second area; a first release layer disposedunder the compensation layer and being in directly contact with thecompensation layer; and a cushion layer disposed under the first releaselayer, wherein the first release layer and the cushion layer overlapwith the first area and do not overlap with the second area, when viewedin a plan view, and wherein an area of the first release layer and anarea of the cushion layer is smaller than an area of the compensationlayer, when viewed in the plan view.
 17. The display device of claim 16,wherein a concave region is provided in an area of the bracket, whichoverlaps with the first area in the plan view.
 18. The display device ofclaim 16, wherein a central portion of the protective film is defined asthe first area and an outer portion of the protective film is defined asthe second area, when viewed in the plan view.